Infection, immune disturbances, and inflammation overlap in the ways that they damage tissues and promote development of cancer. Some studies in this project address the role of specific infections in cancer, including hepatitis C virus, Epstein Barr virus, and malaria in non-Hodgkin lymphoma;Helicobacter pylori in gastric cancer;Chlamydia pneumoniae in lung cancer;and human papillomavirus in penile cancer. Increasingly, it is recognized that microbial diversity (i.e., the microbiome) may play a role in influencing the tissue environment. Other studies examine how general disturbances of immunity may also facilitate development of cancer, such as occurs in solid organ transplant recipients or end stage renal disease. Finally, the project also includes studies to elucidate the role of inflammation as a pathway to cancer, such as caused by chronic infection or autoimmune diseases. The studies are human population-based. Some studies use molecular markers, such as gene markers, serum or tissue markers of infection, and cytokine levels indicating inflammation. Other studies evaluate human genetic polymorphisms that may affect inflammation and immunity and thereby modulate cancer risk..